<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="../vue.global.js"></script>
  </head>

  <body>
    <div id="app">
      <ul>
        <li v-for="n in evenNumbers" :key="n">{{ n }}</li>
      </ul>
      <hr />

      <!-- 双层循环 -->
      <ul v-for="numbers in sets">
        <li v-for="n in even(numbers)" :key="n">{{ n }}</li>
      </ul>
    </div>

    <script>
      Vue.createApp({
        data() {
          return {
            numbers: [1, 2, 3, 4, 5, 6],
            sets: [
              [1, 2, 3, 4, 5, 6],
              [6, 7, 8, 9, 10],
            ],
          };
        },
        computed: {
          evenNumbers() {
            console.log("evenNumbers");
            return this.numbers.filter((number) => number % 2 === 0);
          },
        },
        methods: {
          even(numbers) {
            return numbers.filter((number) => number % 2 === 0);
          },
        },
      }).mount("#app");
    </script>
  </body>
</html>
